As a conventional steering lock device for an automobile, one disclosed in WO2006/092186 (Patent Document 1) is known. A configuration of this steering lock device 100 is shown in FIG. 17. The steering lock device 100 includes a lock member 103, a driven body 106, and a pin 108. The lock member 103 is urged toward a steering shaft 102 of an automobile by a coil spring 101, and capable of being engaged with the steering shaft 102. The driven body 106 is disposed so as to be able to reciprocate in a direction crossing a moving direction of the lock member 103. In addition, a rack 107 is formed on the driven body 106. The rack 107 is coupled with a motor 104 via a gear mechanism 105, and driven by the motor 104. Further, the driven body 106 has a wedge-shaped lock stopper 108. The lock stopper 108 is disposed so as to be able to reciprocate along a moving direction of the driven body 106. A wedged slope 108a of the lock stopper 108 contacts with a stopper hole 109, and the lock stopper 108 shifts the lock member 103 from a lock position to an unlock position along with its slide.
The motor 104 is rotated to its lock direction when the automobile is parked, so that the lock stopper 108 shifts toward a lock position (rightward in FIG. 17) together with the driven body 106 and the lock member 103 shifts to its lock position due to an urging force of a coil spring 101. As a result, an end of the lock member 103 is engaged with the steering shaft 102 to prohibit rotation of the steering shaft 102, and thereby it is made impossible to drive the automobile.
After that, the motor 104 is rotated to its unlock direction, so that the lock stopper 108 shifts toward an unlock position (leftward in FIG. 17) together with the driven body 106. Here, the lock member 103 moves along the slope 108a of the lock stopper 108 and shifts from its lock position to its unlock position. As a result, an engagement between the lock member 103 and the steering shaft 102 is released to enable the rotation of the steering shaft 102, and thereby the automobile is made possible to be steered.